Orthopaedic implants having self-lubricated articulating surfaces designed to reduce wear, corrosion, and ion leaching

ABSTRACT

Mechanical devices such as prosthetic knees, hips, shoulders, fingers, elbows, wrists, ankles, fingers and spinal elements when implanted in the body and used as articulating elements are subjected to wear and corrosion. These prosthetic implants are usually fabricated in modular form from combinations of metallic materials such as stainless steels, Co—Cr—Mo alloys, and Ti—Al—V alloys; plastics such as ultra high molecular weight polyethylene (UHMWPE); and ceramics such as alumina and zirconia. As the articulating surfaces of these materials wear and corrode, products including plastic wear debris, metallic wear particles, and metallic ions will be released into the body, transported to and absorbed by bone, blood, the lymphatic tissue, and other organ systems. The polyethylene wear particles have been shown to produce long term bone loss and loosening of the implant. And, even very low concentrations of metallic wear particles and metallic ions are suspect in causing adverse toxic, inflammatory, and immunologic tissue reactions. This invention provides prosthetic implants having articulating surfaces that exhibit a reduced rate of release of wear debris and metal ions into the body and a method of producing such prosthetic implants.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation-in-Part of and claims priority toU.S. patent application Ser. No. 11/042,150, filed on Jan. 26, 2005, nowU.S. Pat. No. 7,374,642 titled “TREATMENT PROCESS FOR IMPROVING THEMECHANICAL, CATALYTIC, CHEMICAL, AND BIOLOGICAL ACTIVITY OF SURFACES,AND ARTICLES TREATED THEREWITH,” which claims priority to U.S.Provisional Application Ser. No. 60/539,996, filed on Jan. 30, 2004,titled “TREATMENT PROCESS FOR IMPROVING THE MECHANICAL, CATALYTIC,CHEMICAL, AND BIOLOGICAL ACTIVITY OF SURFACES, AND ARTICLES TREATEDTHEREWITH,” the disclosures of which are incorporated herein byreference in their entireties.

FIELD OF THE INVENTION

The present invention relates generally to orthopaedic medicine. Moreparticularly, the present invention relates to an orthopaedic medicinewhere natural articulating joints such as knees, hips, shoulders,elbows, wrists, ankles, fingers and spinal elements are replaced byimplanted mechanical devices to restore diseased or injured skeletaltissue.

BACKGROUND OF THE INVENTION

When mechanical devices such as prosthetic knees, hips, shoulders,fingers, elbows, wrists, ankles, fingers and spinal elements areimplanted in the body and used as articulating elements they aresubjected to wear and corrosion. These prosthetic (orthopaedic) implantsare usually fabricated in modular form with the individual elementsmanufactured from metallic materials such as stainless steels, Co—Cr—Moalloys, Zr alloys, and Ti alloys (Ti—Al—V); plastics such as ultra highmolecular weight polyethylene (UHMWPE); or ceramics such as alumina andzirconia.

As the articulating surfaces of these orthopaedic implants wear andcorrode, products including polyethylene wear particles, metallic wearparticles, and metallic ions are typically released into the body.Thereafter, these wear particles may be transported to and absorbed intobone, blood, lymphatic tissue, and other organ systems. In general,these wear particles have adverse effects. For example, the polyethylenewear particles have been shown to produce long-term bone loss andloosening of the implant. In addition, even very low concentrations ofmetallic wear particles and metallic ions may have adverse immunologictissue reactions. Accordingly, it is desirable to provide an orthopaedicimplant that is capable of overcoming the disadvantages described hereinat least to some extent.

SUMMARY OF THE INVENTION

The foregoing needs are met, to a great extent, by the presentinvention, wherein in one aspect an orthopaedic implant is provided thatin some embodiments provides reduced wear and increased fracture andfatigue resistance in comparison with some existing orthopaedicimplants.

An embodiment of the present invention pertains to an orthopaedicimplant. The orthopaedic implant includes a substrate, nanotexturedsurface, alloyed case layer, and conformal coating. The nanotexturedsurface is disposed upon the substrate. The nanotextured surfaceincludes a plurality of bio-active sites. The alloyed case layer isballistically imbedded on to and below the nanotextured surface. Theconformal coating is disposed upon the alloyed case layer. Thenanotextured surface, alloyed case layer, and the conformal coating aregenerated in the presence of a continuous vacuum.

Another embodiment of the present invention relates to an orthopaedicimplant. The orthopaedic implant includes a first component and secondcomponent. The first component has a first component surface and thesecond component has a second component surface. The first component andthe second component are configured to replace a joint in a patient andthe first component surface and the second component surface areconfigured to mate at an interface. Both the first component and thesecond component include a substrate, nanotextured surface, alloyed caselayer, and conformal coating. The nanotextured surface is disposed uponthe substrate. The nanotextured surface includes a plurality ofbio-active sites. The alloyed case layer is ballistically imbedded on toand below the nanotextured surface. The conformal coating is disposedupon the alloyed case layer. The nanotextured surface, alloyed caselayer, and the conformal coating are generated in the presence of acontinuous vacuum.

Yet another embodiment of the present invention pertains to a method ofcoating a surface of an orthopaedic implant component. In this method,the component is placed into a vacuum chamber. The component has asubstrate that is textured to create a nanotextured surface with aplurality of bio-active sites. The bio-active sites are configured toretain a lubricating layer in response to exposure to a bodily fluid andthe texturing is accomplished by ion beam sputtering the substrate. Inaddition, the nanotextured surface is coated so that surface-relatedproperties are made. In this coating step, ions are imbedded into thesubstrate to generate an alloyed case layer in the substrate and aconformal coating is generated on the alloyed case layer. The texturingand coating steps are performed while maintaining a continuous vacuum inthe vacuum chamber.

There has thus been outlined, rather broadly, certain embodiments of theinvention in order that the detailed description thereof herein may bebetter understood, and in order that the present contribution to the artmay be better appreciated. There are, of course, additional embodimentsof the invention that will be described below and which will form thesubject matter of the claims appended hereto.

In this respect, before explaining at least one embodiment of theinvention in detail, it is to be understood that the invention is notlimited in its application to the details of construction and to thearrangements of the components set forth in the following description orillustrated in the drawings. The invention is capable of embodiments inaddition to those described and of being practiced and carried out invarious ways. Also, it is to be understood that the phraseology andterminology employed herein, as well as the abstract, are for thepurpose of description and should not be regarded as limiting.

As such, those skilled in the art will appreciate that the conceptionupon which this disclosure is based may readily be utilized as a basisfor the designing of other structures, methods and systems for carryingout the several purposes of the present invention. It is important,therefore, that the claims be regarded as including such equivalentconstructions insofar as they do not depart from the spirit and scope ofthe present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial cross-sectional front elevation view illustrating aprosthetic hip joint suitable for use with an embodiment of theinvention.

FIG. 2 is an exploded view illustrating a prosthetic knee joint suitablefor use with an embodiment of the invention.

FIG. 3 is a cross-section detail view at an interface of a pair ofcoated surfaces according to an embodiment of the invention.

FIG. 4 is a cross-section detail view at an interface of a pair ofcoated surfaces according to another embodiment of the invention.

FIG. 5 is a cross-section detail view of a coated surface according toanother embodiment of the invention.

FIG. 6 is a block diagram of a system for coating a surface according toan embodiment of the invention.

FIG. 7, is a scanning electron micrograph image of a test pin surfaceshowing remnants of a lubricating film adhered to the surface of anAl₂O₃ coating.

FIG. 8 is an energy dispersive X-ray analysis showing the presence ofboth calcium and phosphorus cations.

DETAILED DESCRIPTION

The performance of orthopaedic implants 10 of all types and particularlythose that provide motion when implanted in the body can be improveddramatically through the use of embodiments of the present invention.The surface treatments described herein may reduce the generation ofwear debris, corrosion products, and metal ion leaching when applied toorthopaedic implants 10 of various designs and made from a wide varietyof materials. Thus, when so-treated, orthopaedic implants 10 used inpatients to restore skeletal motion impaired by injury or disease mayreduce or eliminate the osteolysis, inflammatory and toxic response, andcarcinogenic effects that can adversely affect conventional implants.This reduction in generation of wear debris is achieved by applyingcoatings to the articulating counterfaces of the implants that are morewear-resistant, corrosion-resistant, and self lubricating than thevarious metallic, ceramic, and plastic materials the implants themselvesare made from.

According to various embodiments of the invention, surfaces oforthopaedic implants may be treated to reduce wear and improvelubrication. In general, modular orthopaedic implants suitable for usewith embodiments of the invention are varied in design and may employarticulating surfaces having different combinations of materials. Insome suitable designs, one element may be a metal alloy and the opposedarticulating element may be a polymer. In other suitable designs oneelement may be a metal alloy and the opposed articulating element may bea similar metal alloy. In yet other suitable designs one element may bea ceramic material and the opposed articulating element may be apolymer. And in still another suitable design one element may be aceramic material and the opposed articulating element may be a similarceramic material. By treating mating surfaces of the orthopaedicimplants as described herein, friction, wear, corrosion, and/or fatiguemay be minimized, resulting in a reduced generation of wear debris andmetal ion release; and improved lubricity.

Orthopaedic implants treated according to various embodiments of thisinvention exhibit reduced generation and release of wear particles,corrosion products, and metallic ions into the body. This reduction innon-biologic contaminants results in a reduced inflammatory response ofthe body to the implant which improves the longevity of the implantresiding in the body. The various embodiments of this invention providean orthopaedic implant that exhibits reduced generation and release ofmetallic, plastic, and ceramic wear particles; corrosion products; andmetallic ions into the body thereby reducing the inflammatory responseof the skeletal tissue to the implant. This results in reducingosteolysis leading to loosening of the orthopaedic implant in the boneinto which it is implanted, and enhances its longevity.

As described herein, a surface treatment may be applied to either one orboth of the articulating opposed surfaces of the implant. The surfacetreatment provides hardness, wear-resistance and corrosion-resistance,and has self lubricating features that further help reduce thegeneration and release of wear debris. This surface treatment may be acoating that is initially alloyed into the articulating surfaces of theimplant and then grown to a finite dimensional thickness from thealloyed surface. This facilitates relatively greater adhesion of thecoating to the articulating surfaces of the implant as compared toconventional coatings. As such, delamination of the coating from thetreated articulating surfaces of the implant is reduced or eliminated.In addition, the surface treatment provides a self-lubricating propertyto further reduce wear between the articulating elements. This isachieved by providing biologically active sites on the surface of thecoatings that attract and hold natural lubricants such as synovial fluidor other extracellular fluids present in the tissue around thearticulating elements. These fluid retentive surfaces act to provide acontinuous thin layer of lubrication between the treated articulatingelements which reduces or eliminates physical contact between thesurfaces of the elements thus reducing or eliminating the generation andrelease of metallic, plastic, and ceramic wear debris; corrosionproducts; and metallic ions into the body.

Conventional case hardening and coating methods often undesirably alterthe bulk properties of the materials to which they are applied.Specifically, the hardness, toughness, fracture-resistance, anddimensionality may be altered in an undesirable manner by conventionalhardening and coating techniques. Post-coating heat-treatments and/ormachining may be employed to return the bulk properties to theseconventionally treated articles. However, many materials can not beheat-treated without detrimental effects. Particular examples ofmaterials that can not be heat treated without detrimental effectsinclude: any of the family of stainless steels, Co—Cr—Mo alloys, Ti—Al—Valloys, Zr alloys; alumina and zirconia ceramics; and plastics. It is anadvantage of embodiments of the invention that the bulk properties ofthe implant material are substantially unaffected by surface treatmentsas described herein. As such, post-coating heat-treating or machiningmay be avoided.

The coating provided by the various surface treatments described hereinmay be applied to a metal substrate. These coatings include hard ceramicmaterial such as aluminum oxide (Al₂O₃, alpha phase), zirconium oxide(Zr₂O), metallic nitrides (such as TiN, Si₃N₄, CrN, ZrN, TaN), and/ormetallic carbides (such as Cr₂C, TiC, WC). The use of these and otherhard ceramic materials further reduces abrasion of the coating. In thismanner, orthopaedic implants 10 that have high bulkfracture/fatigue-resistant properties characteristic of metallicmaterials, and also have the high surface wear- and corrosion-resistantproperties characteristic of hard ceramic materials may be provided byvarious embodiments of the invention. This is achieved by applying aceramic material to the articulating surface of a metallic implant whichminimizes the chance of catastrophic failure of the implant due tofracture of the bulk material.

The method of treating one or both of the articulating opposed bearingsurfaces of the implant as described herein produces a thinnanocrystalline or nearly-amorphous coating that may include multiplecontiguous layers of different materials such as metals (Cr, Ni, Ti, Zr,Al, and others) and hard ceramics such as aluminum oxide (Al₂O₃, alphaphase), zirconium oxide (Zr₂O), or metallic nitrides (such as TiN,Si₃N₄, CrN, ZrN, TaN), or metallic carbides (such as Cr₂C, TiC, WC),each grown directly and sequentially from the previously grown layer. Ingeneral, this coating process may be carried out at a temperature of 600degrees Fahrenheit or less. This reduces or eliminates temperatureinduced changes in bulk properties or dimensions of the treated element.In addition this coating process produces a thin nanocrystalline ornearly-amorphous coating on the articulating surface thereby minimizingthe possibility that intergranular cracks or voids in the coating canallow corrosion and subsequent release of metal ions and/or particlewear debris into the patient. Furthermore, this thin nanocrystalline ornearly-amorphous coating on the articulating surface minimizes thepossibility that intergranular cracks in the coating can propagate intothe underlying substrate to cause it to fail prematurely, as by afatigue mechanism. It is a further advantage that coating applied asdescribed herein are resistant to the effects of gamma ray sterilizationprocedures. Thus, the treated implants can sterilized without degradingthe wear-resistant, corrosion-resistant, and self-lubricating propertiesof the treated implant.

The invention will now be described with reference to the drawingfigures, in which like reference numerals refer to like partsthroughout. FIG. 1 is a partial cross-sectional front elevation viewillustrating a prosthetic hip joint 10 suitable for use with anembodiment of the invention. As shown in FIG. 1, the implant 10 is amulti-element modular mechanical construct for attachment to twoskeletal members. In general the implant 10 is configured to allowmotion between those two skeletal members. The artificial hip iscomprised of an acetabular cup 12, femoral component 14, and in somedesigns an optional liner 16 may be included. The two elements attachedto skeletal members include the acetabular cup 12 and femoral component14. The acetabular cup 12 comprises two surfaces 20 and 22. The surface20 is fastened to the bony acetabulum of the hip, and the surface 22 isconcave in shape and can accept the convex portion of an opposedarticulating element. The femoral component 14 includes a stem portion24 and a spherical portion 26 (the femoral head). The stem portion 24 isinserted into the canal of the femoral bone of the leg and fastenedtherein. The outside surface 28 of spherical portion 26 of the femoralcomponent 14 is mated to the concave surface 22 of the acetabular cup 12and is configured to provide articulation between the leg and hip. Inthis manner, function of a patient's hip may be restored. If included,the liner 16 is interposed between surface 22 and surface 28. In thiscase the convex surface 30 of element 16 is fastened to the concavesurface 22 of the acetabular cup 12, and the concave surface 32 acceptsthe convex surface 28 of the spherical portion 26. The designs of, andmaterials chosen for the acetabular cup 12, spherical portion 26 andliner 16 generally determine the nature and rate of generation of thewear debris and products released into the body.

FIG. 2 is an exploded view illustrating a prosthetic knee joint suitablefor use with an embodiment of the invention. As shown in FIG. 2, thearticulating orthopaedic implant 10 may include an artificial knee. Theartificial knee includes a femoral condyle 38, tibial plateau 40, andtibial insert 42. The femoral condyle 38 and tibial plateau 40 may beattached to skeletal members of a patient. The femoral condyle 38includes two surfaces 44 and 46. The surface 44 is fastened to thefemoral bone of the leg, and surface 46 is convex in shape and isconfigured to accept the concave portion of an opposed articulatingelement such as the tibial insert 42. The tibial plateau 40 includes abottom surface 48 and a top surface 50. The bottom surface 48 isattached to the top of the tibial bone of the leg and fastened thereon.The tibial insert 42 includes a top surface 52 which is mated to theconvex surface 46 and is configured to facilitate articulation of theknee and thereby restore function to the knee. The tibial insert 42includes a bottom surface 54 which is attached to the top surface 50 ofthe tibial plateau 40. Left untreated, the designs of, and materialschosen for the elements 38, 40 and 42 will determine the nature and rateof generation of the wear debris and products released into the body.

A variety of combinations of materials are suitable for use with thecontacting articulating surfaces of elements in modular orthopaedichips, knees and other implants according to various embodiments of theinvention. These combinations include metal-polymer, ceramic-polymer,metal-metal, and ceramic-ceramic. When treated or coated as describedherein, these material combinations reduce friction, wear, and corrosionin modular articulating orthopaedic implants 10. It is an advantage ofembodiments of the invention that undesirable particle debris may bereduced or eliminated by the treatments described herein. Particularexamples of drawbacks associated with untreated conventional materialsare described in Table I and highlight the innovative features of thecurrent invention.

TABLE I Drawbacks of Conventional Implant Material Combinations MaterialCombination Typical Materials Effects Metal-Polymer Metal StainlessSteel, Co—Cr—Mo, Abrasive wear against UHMWPE Ti—Al—V, Zr constantlyremoves passive oxide layer on the metal which releases metal ions whichare potentially toxic and carcinogenic. Polymer UHMWPE Adhesive wearreleases polymeric particle debris. Fatigue wear releases particulatedebris, produces fatigue failure fragments, and plastic deformation andcracking of the UHMWPE. Polymeric wear debris and fragments leads toloosening of the implant. Ceramic-Polymer Ceramic Sintered alumina orzirconia Abrasive wear against UHMWPE less than that seen with metalcomponents. Ceramic wear debris is considered biologically inert PolymerUHMWPE Adhesive wear releases polymeric particle debris. Fatigue wearreleases particulate debris, produces fatigue failure fragments, andplastic deformation and cracking of the UHMWPE. Polymeric wear debrisand fragments leads to loosening of the implant. Metal-Metal MetalCo—Cr—Mo, Ti—Al—V, Zr Abrasive wear against opposed metallic surfaceconstantly removes passive oxide layer on the metal which releases metalions which are potentially toxic and carcinogenic. Adhesive wear againstopposed metallic surface will produce galling with constant generationof particulate metallic particle debris. Ceramic-Ceramic CeramicSintered alumina or Wear rate less than seen with metals zirconia andceramic wear debris considered biologically inert. Bulk ceramicmaterials are brittle and subject to fatigue fracture producing largeceramic fragments and possible catastrophic failure.

Referring to Table I, it is seen that conventional polymeric materialssuch as UHMWPE are subject to abrasive, adhesive, and fatigue wear, allof which contribute to the release of polymeric particle debris. Inaddition the UHMWPE is soft and is subject to bulk plastic deformationand dimensional distortion. The surfaces of metallic components wearingagainst each other are also subject to abrasive, adhesive and fatiguefailure. Abrasive rubbing of opposed metallic surfaces constantlyremoves passive oxide layers on both metal surfaces which release metalions that are potentially toxic and carcinogenic. Adhesive wear betweenthe opposed metal surfaces will produce galling and metal transfer withconstant generation of particulate metallic particle debris. And undercyclic loading conditions the metal surfaces eventually show fatiguewear. Ceramic materials, when wearing against polymer and metal surfacesexhibit low coefficients of friction and generate relatively low levelsof ceramic wear debris. Likewise ceramic elements wearing against eachother produce relatively low levels of ceramic wear debris. However,bulk ceramic materials are brittle and subject to fatigue fractureproducing large ceramic fragments and possible catastrophic failures.

FIG. 3 is a cross-section detail view at an interface between two coatedsurfaces according to an embodiment of the invention. In thisembodiment, the articulating orthopaedic implant 10 includes opposedelements that are both fabricated from metallic materials and thecounter facing surfaces of both are treated to reduce wear, corrosion,ion leaching, and also to be self-lubricated. As shown in FIG. 3, wheninstalled in a patient, a thin layer of lubrication 58 such as synovialfluid or the like is maintained between surfaces of opposingarticulating elements 60 and 62. These opposing articulating elements 60and 62 may be fabricated from a bulk metal 64 and 66 and both have thebulk hardness and fracture-toughness required for optimum performanceand long useful life. In a particular example, the bulk metal 64 and 66may include Co—Cr—Mo. The original surfaces of both elements are shownat 68 and 70. Using an ion beam enhanced deposition (IBED) process,described herein, a ceramic material is first alloyed into and below theoriginal surfaces 68 and 70 of each opposed element 60 and 62. Thepresence of ceramic material in the sub-surface alloyed case layers 72and 74 produces a high concentration of compressive forces in thesurfaces which helps convert retained tensile stresses in the surfacesto compressive stresses with a consequent increase in fracture toughnessof layers 72 and 74. Sub-surface alloyed case layers 72 and 74 alsoprovide bonding zones from which thicker layers of the ceramic materialcan be grown as ceramic coatings of finite thickness, 76 and 78. Sinceceramic coatings 76 and 78 are grown continuously from sub-surfacealloyed case layers 72 and 74, there is no distinct interface betweenthe original surfaces 68 and 70 and the coatings 76 and 78, and thus theceramic coatings generated by this process are relatively less likely todelaminate from the surfaces 68 and 70 as compared to conventionalcoatings.

Furthermore, the IBED process allows a high degree of control over themechanical and metallurgical properties of the ceramic coatings 76 and78. The metallurgical composition can be maintained in a highly uniformmanner throughout the ceramic coatings. As a result, properties such ashardness and wear-resistance can be optimized to reduce or eliminatewear debris generation from the metallic surface beneath the ceramiccoating. The coating grain sizes can further be maintained in thenanometer (1×10⁻⁹ meter) range allowing the coatings to growsubstantially void- and pinhole-free thus eliminating corrosion and ionleaching from the metallic surface beneath the ceramic coating. Themetallurgical composition can also be tailored to provide biologicallyactive sites on the external surfaces (80 and 82) of the ceramic coatingthat attract and hold natural lubricants (synovial or otherextracellular fluids) present in the tissue around the articulatingelements. These fluid retentive surfaces provide a continuously formingthin layer of lubrication 58 between the treated articulating elementsthat reduces or eliminates physical contact between the surfaces of theelements. In this manner, the generation and release of wear debris,corrosion products, and metallic ions into the body is reduced oreliminated.

The IBED process used to form a ceramic coating in and on the surfacesof the metallic articulating elements proceeds as a continuous,uninterrupted, two-step process described in the following Table II:

TABLE II Step 1 (Surface Texturing) Step 2 (Coating) A B A B C D Articleplaced Surface Coating Initial case Thin Thicker in vacuum textured bymaterial layer of conformal coating grown chamber ion beam evolved andcoating coating grown while sputtering deposited on material whilecontinuously surface of alloyed into continuously augmented by articlesurface of augmented by ion beam article ion beam

FIG. 4 is a cross-section detail view of a coated surface according toanother embodiment of the invention. As shown in FIG. 4 the orthopaedicimplant 10 includes elements 84 and 86 in close proximity. In thisembodiment, a multiple layer coating may be generated in and/or on eacharticulating surface of the orthopaedic implant 10. This is achieved byperforming the IBED process to form a second (outer) coating layer inand out from the surface of the first (inner) layer. Referring to FIG.4, one or both top surfaces of the coating (88 and 90) previously formedon the articulating surfaces of the orthopaedic implant 10 are shown at92 and 94. A second material is first alloyed into and below theoriginal surfaces 92 and 94 of the coatings 88 and 90 on each opposedelement 84 and 86. Sub-surface alloyed case layers 96 and 98 alsoprovide bonding zones from which thicker layers of the second materialcan be grown as coatings of finite thickness, 100 and 102. Since thesecond layer coatings 100 and 102 are grown continuously fromsub-surface alloyed case layers 96 and 98, there is no distinctinterface between the original surfaces 92 and 94 of the first coating(88 and 90) and the second coatings 100 and 102, and thus the secondcoatings are relatively less likely to delaminate from the firstcoatings 88 and 90 as compared to conventional coating procedures.Furthermore, the IBED process allows a high degree of control over themechanical and metallurgical properties of the second coatings 100 and102. The metallurgical composition can be maintained highly uniformthroughout the second (outer) coating, thus properties like hardness andwear-resistance can be optimized to reduce or eliminate wear debrisgeneration from the metallic surface or first (inner) coating beneaththe second (outer) coating. The metallurgical composition can also betailored to provide biologically active sites on the external surfaces(104 and 106) of the ceramic coating that attract and hold naturallubricants (synovial or other extracellular fluids) present in thetissue around the articulating elements. These fluid retentive surfacesprovide a continuously forming thin layer of lubrication 108 between thetreated articulating elements which eliminates physical contact betweenthe surfaces of the elements thus eliminating the generation and releaseof wear debris, corrosion products, and metallic ions into the body.

FIG. 5 is a cross-section detail view of a coated surfaces according toanother embodiment of the invention. As shown in FIG. 5, thearticulating opposed element is fabricated from a metallic material andthe counter facing opposed element is fabricated from either a plasticor ceramic material, and the surface of only one element is treated toreduce wear, corrosion, ion leaching and also to be self-lubricated.

As shown in FIG. 5, the articulating orthopaedic implant 10 includesopposed elements 130 and 132. In a particular example, the articulatingelement 130 is fabricated from a bulk metal alloy such as Co—Cr—Mo orTi—Al—V (134) that has the bulk hardness and fracture-toughness requiredfor optimum performance and long useful life. The counter facingarticulating element (132) is fabricated from a bulk plastic or ceramicmaterial. The original surface of the metallic articulating element isshown at 136. Using an IBED process, a ceramic material is first alloyedinto and below the original surface 136 of element 130. The presence ofceramic material in the sub-surface alloyed case layer 138 produces ahigh concentration of compressive forces in the surface which helpsconvert retained tensile stresses in the surface to compressive stresseswith a consequent increase in fracture toughness of layer 138. Thesub-surface alloyed case layer 138 also provides a bonding zone fromwhich a thicker layer of the ceramic material can be grown as a ceramiccoating 140 of finite thickness. Since the ceramic coating 140 is growncontinuously from sub-surface alloyed case layer 138, there is nodistinct interface between the original surface 136 and the coating 140,and thus the ceramic coating is less likely to delaminate from thesurface 136 as compared to conventional coating methods. Furthermore,the IBED process allows a high degree of control over the mechanical andmetallurgical properties of the ceramic coating 140. The metallurgicalcomposition can be maintained highly uniform throughout the ceramiccoating, thus properties like hardness and wear-resistance can beoptimized to eliminate wear debris generation from the metallic surfacebeneath the ceramic coating. And coating grain sizes can be maintainedin the nanometer (1×10⁻⁹ meter) range allowing the coating to grow void-and pinhole-free thus eliminating corrosion and ion leaching from themetallic surface beneath the ceramic coating. The metallurgicalcomposition can also be tailored to provide biologically active sites onthe external surface (142) of the ceramic coating that attract and holdnatural lubricants (synovial or other extracellular fluids) present inthe tissue around the articulating elements. These fluid retentivesurfaces provide a continuously forming thin layer of lubrication 144between the treated and untreated articulating elements that eliminatesphysical contact between the surfaces of the elements thus reducing oreliminating the generation and release of metallic and plastic orceramic wear debris, corrosion products, and metallic ions into thebody.

The IBED process used to form a ceramic coating in and on the surfacesof the metallic articulating elements proceeds as a continuous,uninterrupted, two-step process is outlined below in Table III:

TABLE III Step 1 (Surface Texturing) Step 2 (Coating) A B A B C DArticle placed Surface Coating Initial case Thin Thicker in vacuumtextured by material layer of conformal coating grown chamber ion beamevolved and coating coating grown while sputtering deposited on materialwhile continuously surface of alloyed into continuously augmented byarticle surface of augmented by ion beam article ion beam

FIG. 6 is a block diagram of a system for coating a surface according toan embodiment of the invention. As shown in FIG. 6, the treatmentprocess may be performed in a vacuum vessel 150. A high vacuumenvironment is preferably maintained in the vacuum vessel 150 in orderto allow a high degree of control over the quality of the coating formedin and on the surface of the article. One or more articles 152 may beaffixed to a part platen 154. The part platen 154 is configured toprovide suitable control of positioning of the articles during theseparate cleaning and coating steps. The part platen 154 can rotateabout its axis 156 and tilt about its center 158. The tilt angles androtation rates are chosen such that the surfaces of the parts 152 to betreated are cleaned at the proper angle and the ceramic coating isapplied at the proper angle and with good uniformity on the surfaces tobe coated. A cleaning/augmenting ion beam source 160 is located withinthe vacuum chamber and generates a broad beam of cleaning/augmentingions 162. The broad beam of cleaning/augmenting ions 162 is configuredto perform initial cleaning of the surface of the article by sputtering(first step). An electron gun evaporator 164 is located within thevacuum vessel which produces evaporated coating material 166. Thecoating material 166 is sprayed onto the surface of the articles 152.The electron gun evaporator 164 is configured to contain multiplecharges of coating material if a multiple layer coating is to be grownfrom the articulating surface of the implant. The beam oftexturing/augmenting ions 162 is simultaneously applied to the surfaceof the articles 152 and is used initially to mix the coating materialinto the surface of the articles 152 forming an alloyed case layer inthe surface, and then used to control the composition and crystalstructure of the coating as it is grown out from the alloyed case layer(second step).

If multiple layers of coating material are to be applied, the beam oftexturing/augmenting 162 ions is simultaneously applied to the surfaceof the first coating layer and is used initially to mix or ballisticallyembed the coating material into the surface of the first coating layerforming an alloyed case layer in the first coating layer, and then usedto control the composition and crystal structure of the second coatinglayer as it is grown out from the first coating layer. During both thecleaning and alloying/coating step, the part platen 154 may be rotatedabout its axis 156 and oscillated about its center 158 to facilitateuniform coverage of the articles. A thickness measuring gauge 168 ispositioned near the part platen 154 in order to monitor the arrival ofthe evaporated coating material 166 and control formation of the alloyedsurface layer and then the thicker coating grown from the alloyedsurface layer.

Preferably, the two-step treatment process is carried out sequentiallyin the same vacuum chamber without releasing the high vacuum toatmospheric pressure between steps. If this occurs a latent oxide layerwill form on the cleaned surface and will interfere with the formationof the coating. It is also preferable to accurately control theintensities of the cleaning/augmenting ion beam and the angular positionof the articles to be treated relative to this directional beam suchthat the surface alloyed layer and coating are applied uniformly to thesurface to be treated.

Embodiments of the invention are further illustrated by the followingnon-limiting four Examples in which examples of particular coatingparameter and test data associated with the coated items is presented.

EXAMPLE 1

Samples of Co—Cr—Mo materials used to manufacture the orthopaedicimplants 10 were prepared and coated with a ceramic coating as describedherein. The samples were pins and disks utilized in the standardPin-On-Disk wear test procedure (ASTM F732-00(2006) Standard Test Methodfor Wear Testing of Polymeric Materials Used in Total Joint Prostheses,American Society For Testing and Materials). The wear of the coated pinand disks was measured and compared to the wear found with uncoated pinsand disks manufactured from the same Co—Cr—Mo material.

In this case a two-layer coating was deposited on the pins and disksusing the inventive IBED process. The first (inner) layer was titaniumnitride (TiN) and the second (outer) layer was aluminum oxide (Al₂O₃).The procedures and processing parameters utilized to deposit thetwo-layer coating on the pin and disk sample materials are as follows:

TABLE IV Step 1: Surface Texturing Description Process Parameters A Pin& Disk materials placed in vacuum Vacuum: 1.0E(−07) Torr chamber on arotatable articulated fixture which allows programmed orientation of thedevice during the process. B Surface of the Pin & Disk materials IonSpecies: N textured by ion beam sputtering with the ion Beam Energy:1000 eV beam from the augmenting ion source and Beam Current: 4.4 mA/cm²manipulating the materials such that the Angle of incidence between45-75 sputtering angle of incidence is maintained degrees on thesurfaces to be textured Part Platen Rotation: 30 RPM Time: 10 minutesStep 2: Coating by Vacuum Evaporation, TiN first (inner) layer, Al₂O₃second Description Process Parameters (TiN) Process Parameters (Al₂O₃) AE-gun evaporator used Material: Ti Material: Al₂O₃ to melt and evaporatePart platen held at angle Part platen held at angle coating materialbetween 25 and 75 between 25 and 75 degrees to continuously onto degreesto evaporator flux evaporator flux surface of Pin & Disk. EvolutionRate: 14.5 Å/sec Evolution Rate: 10 Å/sec Part Platen Rotation: 30 RPMPart Platen Rotation: 30 RPM Temperature: <200° F. Temperature: 750° F.B Augmenting ion beam Ion species: N Ion species: Ar used to alloy thefirst Beam Energy: 1000 eV Beam Energy: 1000 eV few layers of the BeamCurrent: 4.4 mA/cm² Beam Current: 2.7 mA/cm² evaporated coatingMaterial: Ti Material: Al₂O₃ material into device Part platen held atangle Part platen held at angle surface of the Pin & between 25 and 75between 25 and 75 degrees to Disk thus forming a degrees to evaporatorflux evaporator flux case layer. Time: 40 seconds Time: 30 seconds Partplaten Rotation: 30 RPM Part platen Rotation: 30 RPM Temperature: <200°F. Temperature: 750° F. C Thin conformal coating Ion species: N Ionspecies: Ar is grown out from the Beam Energy: 800 eV Beam Energy: 800eV alloyed case layer as Beam Current: 4.4 mA/cm² Beam Current: 2.7mA/cm² evaporation of the Material: Ti Material: Al₂O₃ coating materialPart platen held at angle Part platen held at angle continues. between25 and 75 between 25 and 75 degrees to Augmenting ion beam degrees toevaporator flux evaporator flux used to control the Thickness: 50 AThickness: 50 A composition and Part Platen Rotation: 30 RPM Part PlatenRotation: 30 RPM crystal structure of the Temperature: <200° F.Temperature: 750° F. coating as it is grown. D Coating is grown out Ionspecies: N Ion species: Ar from the conformal Beam Energy: 800 eV BeamEnergy: 800 eV coating as evaporation Beam Current: 4.4 mA/cm² BeamCurrent: 2.7 mA/cm² of the coated material Material: Ti Material: Al₂O₃continues. Part platen held at angle Part platen held at angleAugmenting ion beam between 25 and 75 between 25 and 75 degrees to usedto control the degrees to evaporator flux evaporator flux compositionand Thickness: 10,000 Å Thickness: 50,000 Å crystal structure of thePart Platen Rotation: 30 RPM Part Platen Rotation: 30 RPM coating as itis grown. Temperature: <200° F. Temperature: 750° F.

The test conditions and results of the Pin-On-Disk testing are seen inTable V. In this test, the pin and disk sample materials coated with atwo layer TiN/Al₂O₃ coating. As a result of a run for 2,000,000 inchesof wear travel in the Pin-On-Disk tester a volumetric loss of 0.25 mm³is shown. This compares to a volumetric loss of 2.1 mm³ measured for2,000,000 inches of wear travel for uncoated Co—Cr—Mo material.

TABLE V Comparison of Volumetric Wear Loss (ASTM, F732) Sample MaterialLoad (lbs/in²) # of Inches Loss (mm³) IBED Coated Co—Cr—Mo 11,7002,000,000 0.25 Co—Cr—Mo¹ 11,700 2,000,000 2.1 ¹(R. A. Poggie, “A ReviewOf The Effects Of Design, Contact Stress, And Materials On The Wear OfMetal-On-Metal Hip Prostheses,” from Alternate Bearing Surfaces In TotalJoint Replacement, American Society for Testing and Materials, SpecialTechnical Publication STP 1346, 1998)

EXAMPLE 2

A 5 micron thick single layer coating of chromium nitride (Cr₂N) wasdeposited on a 304 stainless steel panel using the inventive processdescribed in U.S. Ser. No. 11/042,150 and then tested for resistance toabrasive wear using a standard Taber Abraser Test. The test was appliedusing the procedure defined by Military Test Specification (MIL-A-8625F)in which an abrasive wheel (Taber, CS-10), impregnated with 50 microndiameter corundum grits, is rubbed against the coating surface with aloading of 2.2 pounds of force, and run for 10,000 abrasion cycles. Thewear loss is measured and presented as the number of microns of coatinglost per 10,000 wear cycles.

The procedures and processing parameters utilized to deposit the singlelayer Cr₂N coating on the 304 stainless steel panel are described inTable VI as follows:

TABLE VI Step 1: Surface Texturing Description Process Parameters APanel material placed in vacuum Vacuum: 1.0E(−07) Torr chamber on arotatable articulated fixture which allows programmed orientation of thedevice during the process. B Surface of the Panel material Ion Species:N textured by ion beam sputtering Beam Energy: 1000 eV with the ion beamfrom the Beam Current: 4.4 mA/cm² augmenting ion source and Angle ofincidence manipulating the materials such between 45-75 degrees that thesputtering angle of Part Platen Rotation: 30 RPM incidence is maintainedon the Time: 10 minutes surfaces to be textured Step 2: Coating byVacuum Evaporation, Cr₂N Process Parameters Description (Cr₂N) A E-gunevaporator used to melt Material: Cr and evaporate coating material Partplaten held at angle continuously onto surface of the between 25 and 75Panel. degrees to evaporator flux Evolution Rate: 12 Å/sec Part PlatenRotation: 30 RPM Temperature: <200° F. B Augmenting ion beam used to Ionspecies: N alloy the first few layers of the Beam Energy: 1000 eVevaporated coating material into Beam Current: 3.4 mA/cm² device surfaceof the Panel thus Material: Cr forming a case layer. Part platen held atangle between 25 and 75 degrees to evaporator flux Time: 40 seconds Partplaten Rotation: 30 RPM Temperature: <200° F. C Thin conformal coatingis grown Ion species: N out from the alloyed case layer Beam Energy: 800eV as evaporation of the coating Beam Current: 3.4 mA/cm² materialcontinues. Augmenting Material: Cr ion beam used to control the Partplaten held at angle composition and crystal between 25 and 75 structureof the coating as it is degrees to evaporator flux grown. Thickness: 50A Part Platen Rotation: 30 RPM Temperature: <200° F. D Coating is grownout from the Ion species: N conformal coating as Beam Energy: 800 eVevaporation of the coated Beam Current: 3.4 mA/cm² material continues.Augmenting Material: Cr ion beam used to control the Part platen held atangle composition and crystal between 25 and 75 structure of the coatingas it is degrees to evaporator flux grown. Thickness: 50,000 Å PartPlaten Rotation: 30 RPM Temperature: <200° F.

The result of the Taber Abrasive Wear Testing is seen in Table VII. TheIBED Cr₂N coating, showed a loss of 0.15 microns (F) in thickness forthe 10,000 cycles of abrasive wear. This compares to a thickness loss of2.82 microns measured for 10,000 cycles of abrasive wear on uncoatedCo—Cr—Mo material with a Rockwell “C” Scale Hardness of 45, that typicalof material used for orthopaedic hip and knee implant components.

TABLE VII Taber Wear Measurement (MIL-A-8625F) # Material Abrasive ofCycles Wear (μ) IBED Cr₂N Coating CS-10 10,000 0.15 Co—Cr—Mo (R_(C) 45)CS-10 10,000 2.82

EXAMPLE 3

A 5 micron thick single layer coating of aluminum oxide (Al₂O₃) wasdeposited on a 304 stainless steel panel as described herein and thentested for resistance to abrasive wear using a standard Taber AbraserTest. The test was applied using the procedure defined by Military TestSpecification (MIL-A-8625F) in which an abrasive wheel (Taber, CS-10),impregnated with 50 micron diameter corundum grits, is rubbed againstthe coating surface with a loading of 2.2 pounds of force, and run for10,000 abrasion cycles. The wear loss is measured and presented as thenumber of microns of coating lost per 10,000 wear cycles.

The procedures and processing parameters utilized to deposit the singlelayer Al₂O₃ coating on the 304 stainless steel panel are illustrated inTable VIII as follows:

TABLE VIII Step 1: Surface Texturing Description Process Parameters APanel material placed in vacuum Vacuum: 1.0E(−07) Torr chamber on arotatable articulated fixture which allows programmed orientation of thedevice during the process. B Surface of the Panel material Ion Species:Ar textured by ion beam sputtering Beam Energy: 1000 eV with the ionbeam from the Beam Current: 4.4 mA/cm² augmenting ion source and Angleof incidence manipulating the materials such between 45-75 degrees thatthe sputtering angle of Part Platen Rotation: 30 RPM incidence ismaintained on the Time: 10 minutes surfaces to be textured Step 2:Coating by Vacuum Evaporation, Al₂O₃ Process Parameters Description(Al₂O₃) A E-gun evaporator used to melt Material: Al₂O₃ and evaporatecoating material Part platen held at angle continuously onto surface ofthe between 25 and 75 Panel. degrees to evaporator flux Evolution Rate:12 Å/sec Part Platen Rotation: 30 RPM Temperature: <200° F. B Augmentingion beam used to Ion species: Ar alloy the first few layers of the BeamEnergy: 1000 eV evaporated coating material into Beam Current: 2.7mA/cm² device surface of the Panel thus Material: Al₂O₃ forming a caselayer. Part platen held at angle between 25 and 75 degrees to evaporatorflux Time: 40 seconds Part platen Rotation: 30 RPM Temperature: <200° F.C Thin conformal coating is grown Ion species: Ar out from the alloyedcase layer Beam Energy: 800 eV as evaporation of the coating BeamCurrent: 2.7 mA/cm² material continues. Augmenting Material: Al₂O₃ ionbeam used to control the Part platen held at angle composition andcrystal between 25 and 75 structure of the coating as it is degrees toevaporator flux grown. Thickness: 50 A Part Platen Rotation: 30 RPMTemperature: <200° F. D Coating is grown out from the Ion species: Arconformal coating as Beam Energy: 800 eV evaporation of the coated BeamCurrent: 2.7 mA/cm² material continues. Augmenting Material: Al₂O₃ ionbeam used to control the Part platen held at angle composition andcrystal between 25 and 75 structure of the coating as it is degrees toevaporator flux grown. Thickness: 50,000 Å Part Platen Rotation: 30 RPMTemperature: <200° F.

The result of the Taber Abrasive Wear Testing is seen in Table IX. TheIBED Al₂O₃ coating, showed a loss of 0.07 microns (μ) in thickness forthe 10,000 cycles of abrasive wear. This compares to a thickness loss of2.82 microns measured for 10,000 cycles of abrasive wear on uncoatedCo—Cr—Mo material with a Rockwell “C” Scale Hardness of 45, that typicalof material used for orthopaedic hip and knee implant components.

TABLE IX Taber Wear Measurement (MIL-A-8625F) # of Material AbrasiveCycles Wear (μ) IBED Al₂O₃ Coating CS-10 10,000 0.07 Co—Cr—Mo (R_(C) 45)CS-10 10,000 2.82

EXAMPLE 4

Pin and disk samples were prepared from Co—Cr—Mo material used tomanufacture orthopaedic implants, and then coated with a ceramic coatingas described herein in order to test the fluid retentive properties ofthe deposited ceramic. In this case a two-layer coating was deposited onthe Co—Cr—Mo pin and disk using the inventive IBED process. The first(inner) layer was titanium nitride (TiN) and the second (outer) layerwas aluminum oxide (Al₂O₃). The procedures and processing parametersutilized to deposit the two-layer coating on the Co—Cr—Mo pin and disksamples are illustrated in Table X as follows:

TABLE X Step 1: Surface Texturing Description Process Parameters A Pin &Disk materials placed in vacuum Vacuum: 1.0E(−07) Torr chamber on arotatable articulated fixture which allows programmed orientation of thedevice during the process. B Surface of the Pin & Disk materials IonSpecies: N textured by ion beam sputtering with the Beam Energy: 1000 eVion beam from the augmenting ion Beam Current: 4.4 mA/cm² source andmanipulating the materials Angle of incidence between 45-75 such thatthe sputtering angle of degrees incidence is maintained on the surfacesPart Platen Rotation: 30 RPM to be textured Time: 10 minutes Step 2:Coating by Vacuum Evaporation, TiN first (inner) layer, Al₂O₃ secondDescription Process Parameters (TiN) Process Parameters (Al₂O₃) A E-gunevaporator Material: Ti Material: Al₂O₃ used to melt and Part platenheld at angle Part platen held at angle evaporate coating between 25 and75 between 25 and 75 degrees to material degrees to evaporator fluxevaporator flux continuously onto Evolution Rate: 14.5 Å/sec EvolutionRate: 10 Å/sec surface of Pin & Part Platen Rotation: 30 RPM Part PlatenRotation: 30 RPM Disk. Temperature: <200° F. Temperature: 750° F. BAugmenting ion Ion species: N Ion species: Ar beam used to alloy BeamEnergy: 1000 eV Beam Energy: 1000 eV the first few layers Beam Current:4.4 mA/cm² Beam Current: 2.7 mA/cm² of the evaporated Material: TiMaterial: Al₂O₃ coating material Part platen held at angle Part platenheld at angle into device surface between 25 and 75 between 25 and 75degrees to of the Pin & Disk degrees to evaporator flux evaporator fluxthus forming a Time: 40 seconds Time: 30 seconds case layer. Part platenRotation 30 RPM Part platen Rotation: 30 RPM Temperature: <200° F.Temperature: 750° F. C Thin conformal Ion species: N Ion species: Arcoating is grown Beam Energy: 800 eV Beam Energy: 800 eV out from theBeam Current: 4.4 mA/cm² Beam Current: 2.7 mA/cm² alloyed case layerMaterial: Ti Material: Al₂O₃ as evaporation of Part platen held at anglePart platen held at angle the coating between 25 and 75 between 25 and75 degrees to material continues. degrees to evaporator flux evaporatorflux Augmenting ion Thickness: 50 A Thickness: 50 A beam used to PartPlaten Rotation: 30 RPM Part Platen Rotation: 30 RPM control theTemperature: <200° F. Temperature: 750° F. composition and crystalstructure of the coating as it is grown. D Coating is grown Ion species:N Ion species: Ar out from the Beam Energy: 800 eV Beam Energy: 800 eVconformal coating Beam Current: 4.4 mA/cm² Beam Current: 2.7 mA/cm² asevaporation of Material: Ti Material: Al₂O₃ the coated matenal Partplaten held at angle Part platen held at angle continues. between 25 and75 between 25 and 75 degrees to Augmenting ion degrees to evaporatorflux evaporator flux beam used to Thickness: 10,000 Å Thickness: 50,000Å control the Part Platen Rotation: 30 RPM Part Platen Rotation: 30 RPMcomposition and Temperature: <200° F. Temperature: 750° F. crystalstructure of the coating as it is grown.

An additional set of pin-on-disk samples was prepared from solid, singlecrystal, alpha phase Al₂O₃. The counter facing surfaces of thispin-on-disk set would not have the same surface nanostructure, and thusfluid-retentive properties, as would the Al₂O₃ coating deposited on theCo—Cr—Mo samples using the inventive process.

Both sample pin and disk sets were tested according to the standardpin-on-disk wear test procedure (ASTM F732-00 (2006) “Standard TestMethod for Wear Testing of Polymeric Materials Used in Total JointProstheses, American Society for Testing and Materials”). The sampleswere immersed in defined bovine calf serum as a lubricant (Hyclone Labs:Cat. No. SH30073.04) during the entirety of the test. After completionof 2,000,000 cycles in the pin-on-disk test, both sample sets werecarefully dried and the surface the pins imaged using scanning electronmicroscopy (SEM), and the surface composition analyzed with energydispersive X-ray analysis (EDAX).

No residue was detected by either SEM imaging or EDAX analysis on thesurface of the single crystal, alpha phase, pin indicating that thesurface of the solid Al₂O₃ pin did not have the properties of afluid-retentive surface. The IBED-coated Co—Cr—Mo pin surface didhowever show remnants of a film that had been retained on the surface ofthe Al₂O₃ coating. FIG. 7, is a scanning electron micrograph image ofthe pin surface showing remnants of the lubricating film still adheredto the surface of the Al₂O₃ coating. FIG. 8 is an energy dispersiveX-ray analysis showing the presence of both Ca and P cations which areinorganic elements present in the defined bovine calf serum proteins.Thus it is confirmed that the structure and surface activity of Al₂O₃coatings as deposited by the inventive IBED process acts as a fluidretentive surface which maintains the self-lubricating performance oforthopaedic implants so-treated.

CONCLUSIONS

The orthopaedic implants 10 with surface treatments provided by thisinvention will generate less debris in the form of wear products,corrosion products, and metallic ion leaching which are liberated andtransported to bone, blood, the lymphatic system, and other internalorgans. This will result in less inflammation, toxicity, and immuneresponse resulting in increased longevity of the orthopaedic implant 10and less adverse effects on the patient. The surface treatments can beapplied to a variety of the materials used to fabricate the articulatingelements of the modular orthopaedic implants 10, and are useful for avariety of combinations of metal, ceramic, and polyethylene articulatingelements.

The many features and advantages of the invention are apparent from thedetailed specification, and thus, it is intended by the appended claimsto cover all such features and advantages of the invention which fallwithin the true spirit and scope of the invention. Further, sincenumerous modifications and variations will readily occur to thoseskilled in the art, it is not desired to limit the invention to theexact construction and operation illustrated and described, andaccordingly, all suitable modifications and equivalents may be resortedto, falling within the scope of the invention.

What is claimed is:
 1. An orthopaedic implant comprising: a firstcomponent, the first component having a first component surface; and asecond component, the second component having a second componentsurface, wherein the first component and the second component areconfigured to replace a joint in a patient and the first componentsurface and the second component surface are configured to mate at aninterface, wherein both the first component and the second componentinclude: a metal substrate selected from the group consisting ofstainless steels, Co—Cr—Mo alloys, Zr alloys, and Ti alloys; ananotextured surface disposed directly upon the metal substrate havingsurface features in a size of 10-9 meters; a ceramic coating selectedfrom the group consisting of: Al₂O₃ (alpha phase), zirconium oxide(Zr₂O); metallic nitrides; and metallic carbides conforming to thenanotextured surface and including a plurality of bio-active sitesconfigured to attract and retain calcium and phosphorous cations; and atransition zone disposed between the metal substrate and the ceramiccoating, wherein the transition zone includes a concentration gradienttransitioning from the metal substrate to the ceramic coating andwherein there is no distinct interface between the metal substrate andthe ceramic coating.
 2. The orthopaedic implant according to claim 1,wherein the nanotextured surface is configured to improve lubricity ofthe orthopaedic implant in the presence of bodily fluids.
 3. Theorthopaedic implant according to claim 2, wherein the plurality ofbio-active sites are configured to improve lubricity of the orthopaedicimplant by retaining calcium and phosphorous cations from synovial fluidupon the nanotextured surface.
 4. The orthopaedic implant according toclaim 1, wherein the ceramic coating is imbedded to a depth of about 5nanometers below the nanotextured surface.
 5. The orthopaedic implantaccording to claim 1, wherein a grain structure of the ceramic coatingis substantially amorphous.
 6. The orthopaedic implant according toclaim 1, wherein the nanotextured surface is generated with adirectional ion beam sputtering device.
 7. The orthopaedic implantaccording to claim 1, wherein the ceramic coating is generated with anion beam enhanced deposition (IBED) process.
 8. An orthopaedic implantto replace a joint in a patient, the orthopaedic implant comprising: afirst component having a first component surface; and a second componenthaving a second component surface, wherein the first component and thesecond component are selected from the group consisting of: anacetabular cup; a femoral component; a femoral condyle; a tibialplateau; and a tibial insert, wherein the second component surface isselected from the group consisting of: a metal; a ceramic; and an ultrahigh molecular weight polymer, wherein the first component surface andthe second component surface are configured to mate at an interface,wherein the first component surface includes: a metal substrate selectedfrom the group consisting of stainless steels, Co—Cr—Mo alloys, Zralloys, and Ti alloys; a nanotextured surface disposed directly upon themetal substrate having surface features in a size of 10-9 meters; aceramic coating selected from the group consisting of: Al₂O₃ (alphaphase), zirconium oxide (Zr₂O); silicon nitride (Si₃N₄), metallicnitrides; and metallic carbides conforming to the nanotextured surfaceand including a plurality of bio-active sites configured to attract andretain calcium and phosphorous cations; and a transition zone disposedbetween the metal substrate and the ceramic coating, wherein thetransition zone includes a concentration gradient transitioning from themetal substrate to the ceramic coating and wherein there is no distinctinterface between the metal substrate and the ceramic coating.
 9. Theorthopaedic implant according to claim 8, wherein the nanotexturedsurface is configured to improve lubricity of the orthopaedic implant inthe presence of bodily fluids.
 10. The orthopaedic implant according toclaim 9, wherein the plurality of bio-active sites are configured toimprove lubricity of the orthopaedic implant by retaining calcium andphosphorous cations from synovial fluid upon the nanotextured surface.11. The orthopaedic implant according to claim 8, wherein the ceramiccoating is imbedded to a depth of about 5 nanometers below thenanotextured surface.
 12. The orthopaedic implant according to claim 8,wherein a grain structure of the ceramic coating is substantiallyamorphous.
 13. The orthopaedic implant according to claim 8, wherein thenanotextured surface is generated with a directional ion beam sputteringdevice.
 14. The orthopaedic implant according to claim 8, wherein theceramic coating is generated with an ion beam enhanced deposition (IBED)process.